αCGRP, a neuropeptide widely distributed in bone tissue, has been demonstrated as a physiological activator of bone formation. However, the regulation of αCGRP on the osseointegration of dental titanium implants is not well understood. In this study, mouse primary calvarial osteoblasts were obtained and cultured on smooth, rough (SLA), and chemically modified (SLActive) titanium discs coated with or without αCGRP (10-8 M). Scanning electron microscopy and immunofluorescence staining demonstrated that αCGRP promoted cellular adhesion on all three titanium surfaces. MTT colorimetric assay and flow cytometry results displayed an increase in cell growth on all titanium surfaces coated with αCGRP from 3 to 7 days post-seeding. Furthermore, cell growth differed when cultured on different titanium surfaces (smooth> SLA> SLActive). In addition, αCGRP upregulated the mRNA expression of ALP and OCN on SLA and SLActive surfaces from 7 to 14 days. Immunofluorescence results further confirmed that osteoblasts secreted more ALP when cultured on αCGRP-coated surfaces. In addition, αCGRP pre-coated surfaces formed more Alizarin red-positive nodules after culture for 21 days. Taken together, our data indicated that coating titanium discs with αCGRP enhanced the adhesion, proliferation, differentiation, and mineralization of osteoblasts, particularly on SLActive surfaces.
Mesenchymal stem cells (MSCs) derived from dental tissues have gained attention in the field of regenerative medicine, in part because they can be obtained from deciduous or extracted teeth. This study aims to investigate the potential of dental pulp-derived MSCs (DP-MSCs) to differentiate into cells with hepatocyte function and to examine the therapeutic effects of these cells on acute chemical liver injuries of rats. MSC fractions from dental pulp were cultured using specific reagents containing activin A and hepatocyte growth factor (HGF). Albumin, fibrinogen, and urea production were assessed and their specific mRNAs were detected by reverse transcription (RT)-PCR. Therapeutic effects of DP-MSCs on rats with acute chemical injuries induced by concanavalin A (ConA) and D-galactosamine (D-gal) were also investigated. DP-MSCs differentiated into polygonal hepatocyte-like cells (HLCs) that produced albumin and converted ammonium to urea. Importantly, HNF4α, which is a liver-specific transcription factor, was expressed in HLCs, confirming the liver-specific properties of HLCs. Administration of HLCs induced significant improvements in liver function following hepatic injury in rats. Thus, DP-MSCs could differentiate into cells with hepatic function. The potential contribution of these cells in regenerative medicine for refractory liver diseases is expected.
At present, a large number of people are suffering from low back pain, which becomes an urgent public health concern, intervertebral disc degeneration (IDD) is one of the most significant reasons of this disease. This study is aimed to select an optimal needle size to establish a rabbit IDD model by intervertebral disc puncture and the validity was verified by magnetic resonance imaging, histology and immunohistochemical staining. We divided 12 rabbits into four groups of 3 randomly with number table method, including 1 control group and 3 experimental groups. Then the lumbar 3/4 (L3/4), lumbar 4/5 (L4/5) and lumbar 5/6 (L5/6) discs were punctured by 14G, 16G and 21G needles respectively. According to the MRI and histology, the 16G-needle-punctured disc showed a progressive degeneration, the 14G-needle-punctured disc degenerated acutely one week after the operation while the 21G-needle-punctured disc did not show much degeneration. To sum up, the 16 G needle is the most suitable for making a model of IDD, which can replicate the occurrence, development and outcome of various histopathology of IDD in clinic. Although the 14G needle can cause the acute intervertebral disc injury, it is not an ideal approach to establish an IDD model. 21G needle causes little disc degeneration inversely, and it could be a promising approach to inject kinds of medicine to treat or prevent IDD.
Diurnal variations in bone remodeling, which are regulated by the central circadian clock in the suprachiasmatic nuclei, have previously been identified. Glucocorticoids induce a circadian rhythm in osteoclasts, causing a circadian rhythm in bone resorption. It has been reported that the extent of experimental tooth movement (ETM) also exhibits diurnal variations, but this has not been thoroughly investigated. The aim of this study was to examine the role of glucocorticoids in the diurnal variations in the extent of ETM. Male C57BL6/J mice were divided into three groups: the whole-day group (WDG); ETM was performed during both the light and dark periods, the light period group (LPG); ETM was performed during the light period (7:00–19:00), and the dark period group (DPG); ETM was performed during the dark period (19:00–7:00). Orthodontic force was applied for a total of 48 hr in all groups. A piece of an orthodontic elastic band was inserted between the right upper first and second molars (M1 and M2) according to the Waldo method. During the study period, the distance between M1 and M2 increased by 185.1±7.0 μm in the WDG, 186.0±6.6 μm in the LPG, and 152.7±9.9 μm in the DPG. The amount of ETM-induced tooth movement was significantly larger in the WDG and LPG than in the DPG. The osteoclast surface/bone surface (compressed side) and osteoclast number/bone surface (compressed side) ratios were also significantly larger in the WDG and LPG than in the DPG. Consistent with the results of osteoclast parameters, the immune reactivity of receptor activator of nuclear factor-κB ligand (RANKL) was higher in the WDG and LPG than in the DPG. Adrenalectomy eliminated the differences in osteoclast parameters, RANKL immune reactivity and the extent of ETM between the LPG and DPG. These differences were restored by the daily administration of the synthetic glucocorticoid dexamethasone to adrenalectomized mice. These results suggest that circulating glucocorticoids contribute to the diurnal variations in the osteoclast parameters which result in the diurnal variation of the tooth movement, and the diurnal variation of RANKL immune reactivity may contribute to it.
With the ultimate aim of developing a novel optimal dentin-bonding system for Er:YAG laser-irradiated dentin, we investigated the adhesion-promoting effects of acid-conditioning and priming with hydrophilic monomers on the bonding performance of the resin-modified glass-ionomer bonding system (RMGI) to laser-irradiated dentin. Results showed that acid-conditioning with a solution of 10% citric acid and 2% ferric chloride followed by priming with 4-methacryloxyethyl trimellitic acid and 2-hydroxyethyl methacrylate was effective for improving the early bond strength and bonding durability of RMGI to Er:YAG laser-irradiated dentin.
Use of low-intensity pulsed ultrasound (LIPUS) as a clinical tool is expected to accelerate bone-titanium integration in dental implant therapy. This study aimed to evaluate the effects of LIPUS treatment on bone marrow cells cultured under osteogenic conditions on the roughened surface of titanium disks in vitro. Bone marrow cells, obtained from the femora of 8-wk-old rats, were suspended in osteogenic-inducing medium. Cells were cultured on acid-etched titanium disks and exposed to LIPUS of 3.0 MHz sine wave frequency, repeated at 100 Hz with a spatial average intensity of 40 mW/cm2 for 15 min/d from day 3 after primary seeding (LIPUS group). The control group was cultivated in the same manner. Cell proliferation, expression of osteoblastic genes, synthesis of collagen, and mineralization were compared between the 2 groups. No significant difference was observed in the cell number between the LIPUS and the control groups on days 5 and 7. The expression of osteocalcin and osteopontin genes were upregulated in the LIPUS group compared with that in the control group. The production of collagen, assessed by Sirius Red staining on day 14, and mineralization, assessed with Alizarin Red S staining on day 14 and 21, were both increased in the LIPUS group relative to the control group. Treatment with LIPUS did not affect the proliferation of osteoblastic cells cultured on roughened titanium disks, whereas it affected the acceleration of osteoblastic differentiation, synthesis of collagen, and calcification.
The effectiveness of osteoclast inhibitors for high-turnover osteoporosis-related bone fracture is slightly unclear. This study aimed to examine the effectiveness of continuous administration of reveromycin A (RMA) and bisphosphonate (BP) in an osteoprotegerin knockout (OPG KO) model. The study included 8-week-old male OPG KO mice. The OPG KO mice received continuous saline (OPG SA group, n = 4), BP (OPG BP group, n = 4), or RMA (OPG RMA group, n = 4). The study also included wild-type mice as controls (administered saline; Wild SA group, n = 4). We found that serum alkaline phosphatase activation (parameter for full-body bone formation) was significantly higher in the OPG SA group than in the Wild SA, OPG BP, and OPG RMA groups and was significantly lower in the OPG BP group than in the OPG RMA group (all p < 0.001). Additionally, the blood tartrate-resistant acid phosphatase concentration (parameter for osteoclast activation) was significantly higher in the OPG SA group than in the Wild SA, OPG BP, and OPG RMA groups and was significantly lower in the OPG BP group than in the OPG RMA group (all p < 0.001). Significant increases in the bone healing score and significant decreases in the callus area were observed from 10 to 21 days after the procedure in the OPG SA and OPG RMA groups (all p < 0.001). Moreover, at 21 days, the score was significantly lower (p < 0.01) and the callus area was significantly larger (p < 0.001) in the OPG BP group than in the OPG SA and OPG RMA groups. In the OPG RMA group, the fractured bone segment was indistinguishable from the rest of the bone at 21 days. Our results suggest that RMA is an effective and safe alternative to BP for the treatment of high-turnover osteoporosis.
The aim of this study was to determine the effect of topical irrigation with a solution of ozone (O3) water on soft tissue healing after dental implantation. Recruited patients underwent similar oral surgeries (dental implantation) on both sides of their upper jaws. One randomly selected site was irrigated with 10 ml of O3 water solution immediately following surgery and after 3 days. The other side was irrigated with normal saline. Wound healing was assessed 24 hours and 5 days following the surgery. Early healing scores (EHSs) were registered. Post-operative instructions were provided to all patients. Of them, 12 were male and 16 were female. Tissues at the sites of surgery were thin in 13 patients and thick in 15 patients. The proportions of sites irrigated with ozonated water that had merged incision margins, no fibrin at the incision margins, and no signs of inflammation were higher than those of sites irrigated with saline on days 1 and 5 following the surgery. On day 1, the median total EHSs for re-epithelization, hemostasis, and inflammation were significantly higher for intervention sites than those for control sites. However, no significant differences were observed in the studied parameters between the intervention and control sites on day 5. O3 treatment enhances soft tissue healing in the immediate postoperative period. The assessment of long-term clinical outcomes of O3 treatment should be investigated further.
We aimed to evaluate the esthetic effects of immediate implantation and restoration after minimally invasive tooth extraction on maxillary central incisors, and the influence on the reconstruction of labial bone lamella. From January 2014 to September 2018, 108 patients who underwent minimally invasive tooth extraction, implantation and restoration due to residual crown of a single maxillary central incisor in our hospital were divided into three groups according to different treatment methods. Group A (n=41) received delayed implantation and immediate restoration, group B (n=32) underwent immediate implantation and delayed restoration, and group C (n=35) was subjected to immediate implantation and restoration. On the day of restoration and 1 year later, the esthetic effects were assessed by using white esthetic index and pink esthetic index (PES). One year after restoration, the degree of satisfaction was evaluated with the visual analog scale. The implantation success rate and 1-year retention rate of the three groups all reached 100.00%. On the day of restoration and 1 year later, the PES values of groups A, B, and C followed an ascending order, with significant intergroup differences (P<0.05). The values of the three groups 1 year after restoration were significantly higher than those on the day of restoration (P<0.05). Group C was significantly more satisfactory about the overall esthetics, height of attachment and chewing function than groups A and B (P<0.05). Immediate implantation and restoration after minimally invasive tooth extraction can significantly promote the early induction of gingival reshaping, improve the esthetics of soft tissue around the implant, and augment patients’ satisfaction.
This study aimed to compare implant stability, bone loss, and bone density using the mineralized plasmatic matrix (MPM) and conventional bone grafting methods. Patients were recruited in a stratified sample and each received 2 implants one at each side of their upper jaws. MPM was randomly placed in the surgical site around one implant on one side while a conventional graft, was placed on the other side in a cross-over design clinical trial. A total of 84 implants were placed in 42 patients. A total of 42 implants utilized conventional grafts (GM1) and a total of 42 implants utilized mineralized plasmatic matrix (GM2). Mean Perio test measurements for implants in the group (GM1) were lower than that for implants in the group (GM2) (1.21±3.0 versus 3.57±2.9). Mean radiographic density at grafted sites with GM2 was: 665.2±236.5 whereas for GM1 it was: 577.8±201.2. Implant stability with MPM in males was significantly higher than females (P<0.001). Bone graft loss with MPM in males was significantly less than females (P=0.001). There were no differences between older and younger patients regarding implant stability, bone loss, and bone density (P>0.05). It is concluded that utilizing MPM in implants may be associated with better implant treatment outcomes of implant stability, bone graft loss, and density when compared to conventional bone grafts. Gender but not age differences may be noticed when comparing implant stability and bone graft loss in implants utilizing MPM.